80 
Gerard R. Case 
anterior, lateral and posterior, from both upper and lower jaws. Sites 1 
and 2. 
Description: — Small-sized teeth, approximately 1 to 1.5 cm wide. The 
teeth of Squalicorax kaupi are about 1/3 the size of those of Squalicorax 
pristodontus . They show an indentation on the side of the blade directed 
towards the commissure of the mouth, whereas the teeth of S. pristodontus 
have a full, arcuate shape and no indentation of the blade. I assume that 
the upper and lower teeth are quite similar, showing no heterodonty, so it 
is difficult to be certain whether a given tooth comes from the upper or 
lower jaw. 
Squalicorax pristodontus (Agassiz) 
Corax pristodontus Agassiz, 1843:224, PI. 26, Figs. 9-13. 
Material : — PU 22420, a lower lateral tooth (Figs. 7-8). Site 1. 
Description: — Teeth of fairly large size, averaging between 2 and 3 cm 
wide. Large crescent-shaped blade with no indentation, as distinct from 
S. kaupi. Roots, as with S. kaupi , are quite flattened, with or without an 
apical foramen on the lingual face, and with or without fenestration or 
multiple foramina on the upper portion of the root processes on the labial 
face. Upper and lower teeth are similar, as with S. kaupi. 
Discussion: — The teeth of S. pristodontus are quite distinctive. Although 
some specimens have been recovered from formations as early as the Late 
Campanian, the species is quite uncommon in pre-Maestrichtian out- 
crops, and is by far more abundant in the Middle and Late Maestrichtian 
stages of the Upper Cretaceous. Its geographic range is much like that of 
S. kaupi. Squalicorax pristodontus is most abundant in the Middle Maestrich- 
tian (Navesink Marl) of New Jersey, the Late Maestrichtian (Kemp Clay 
Member, formerly the “Littig,” of the Navarro Group) in northeast and 
central Texas, and the Late Maestrichtian (“ Couche trois” des phosphates) of 
Morrocco, North Africa. 
Clade EUSELACHIFORMES 
Order EUSELACHII 
Family MITSUKURINIDAE 
Scapanorhynchus Woodward, 1889 
Scapanorhynchus texanus (Roemer) 
Lamna texana Roemer, 1852:29, PI. 1, Fig. 7. 
Material: — PU 22421A, an upper lateral tooth (Figs. 9-10), and PU 
22421 B, a lower anterior tooth (Figs. 11-12); about two dozen additional 
